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| author | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2018-10-24 11:36:02 +0200 |
|---|---|---|
| committer | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2018-10-25 12:19:14 +0000 |
| commit | 8455ab6cb29fcccf44977c517689a8ad26781140 (patch) | |
| tree | 9064ae1afb3dc3a42b7227b13f5b636832936dbb | |
| parent | 80017a1c7f829355edce61d5d50196cd1e13dcdd (diff) | |
| download | qtimageformats-8455ab6cb29fcccf44977c517689a8ad26781140.tar.gz | |
tiffhandler: improve stripsize
libtiff's default stripsize is tiny (8KB), so splitting the image into
such strips on writing would significantly hurt the compression
rate. Aim for 4MB strips instead.
Task-number: QTBUG-70820
Change-Id: I07a9a8c81edf62e802b4ae8d6729a76df15e42ac
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
| -rw-r--r-- | src/plugins/imageformats/tiff/qtiffhandler.cpp | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/src/plugins/imageformats/tiff/qtiffhandler.cpp b/src/plugins/imageformats/tiff/qtiffhandler.cpp index 84221d6..d321554 100644 --- a/src/plugins/imageformats/tiff/qtiffhandler.cpp +++ b/src/plugins/imageformats/tiff/qtiffhandler.cpp @@ -495,6 +495,15 @@ static QVector<QRgb> effectiveColorTable(const QImage &image) return colors; } +static quint32 defaultStripSize(TIFF *tiff) +{ + // Aim for 4MB strips + qint64 scanSize = qMax(tmsize_t(1), TIFFScanlineSize(tiff)); + qint64 numRows = (4 * 1024 * 1024) / scanSize; + quint32 reqSize = static_cast<quint32>(qBound(qint64(1), numRows, qint64(UINT_MAX))); + return TIFFDefaultStripSize(tiff, reqSize); +} + bool QTiffHandler::write(const QImage &image) { if (!device()->isWritable()) @@ -559,7 +568,7 @@ bool QTiffHandler::write(const QImage &image) if (!TIFFSetField(tiff, TIFFTAG_PHOTOMETRIC, photometric) || !TIFFSetField(tiff, TIFFTAG_COMPRESSION, compression == NoCompression ? COMPRESSION_NONE : COMPRESSION_LZW) || !TIFFSetField(tiff, TIFFTAG_BITSPERSAMPLE, 1) - || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, TIFFDefaultStripSize(tiff, 0))) { + || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, defaultStripSize(tiff))) { TIFFClose(tiff); return false; } @@ -595,7 +604,7 @@ bool QTiffHandler::write(const QImage &image) if (!TIFFSetField(tiff, TIFFTAG_PHOTOMETRIC, photometric) || !TIFFSetField(tiff, TIFFTAG_COMPRESSION, compression == NoCompression ? COMPRESSION_NONE : COMPRESSION_LZW) || !TIFFSetField(tiff, TIFFTAG_BITSPERSAMPLE, 8) - || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, TIFFDefaultStripSize(tiff, 0))) { + || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, defaultStripSize(tiff))) { TIFFClose(tiff); return false; } @@ -603,7 +612,7 @@ bool QTiffHandler::write(const QImage &image) if (!TIFFSetField(tiff, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_PALETTE) || !TIFFSetField(tiff, TIFFTAG_COMPRESSION, compression == NoCompression ? COMPRESSION_NONE : COMPRESSION_LZW) || !TIFFSetField(tiff, TIFFTAG_BITSPERSAMPLE, 8) - || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, TIFFDefaultStripSize(tiff, 0))) { + || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, defaultStripSize(tiff))) { TIFFClose(tiff); return false; } @@ -656,7 +665,7 @@ bool QTiffHandler::write(const QImage &image) || !TIFFSetField(tiff, TIFFTAG_COMPRESSION, compression == NoCompression ? COMPRESSION_NONE : COMPRESSION_LZW) || !TIFFSetField(tiff, TIFFTAG_SAMPLESPERPIXEL, 3) || !TIFFSetField(tiff, TIFFTAG_BITSPERSAMPLE, 8) - || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, TIFFDefaultStripSize(tiff, 0))) { + || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, defaultStripSize(tiff))) { TIFFClose(tiff); return false; } @@ -688,7 +697,7 @@ bool QTiffHandler::write(const QImage &image) || !TIFFSetField(tiff, TIFFTAG_SAMPLESPERPIXEL, 4) || !TIFFSetField(tiff, TIFFTAG_BITSPERSAMPLE, 8) || !TIFFSetField(tiff, TIFFTAG_EXTRASAMPLES, 1, &extrasamples) - || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, TIFFDefaultStripSize(tiff, 0))) { + || !TIFFSetField(tiff, TIFFTAG_ROWSPERSTRIP, defaultStripSize(tiff))) { TIFFClose(tiff); return false; } |